Buildings like these are vulnerable to collapse during an earthquake, and the city is considering mandatory retrofit work.

Photo: Lea Suzuki, The Chronicle

Buildings like these are vulnerable to collapse during an...

Image 2 of 6

Robert Link of S&L Realty walks through one of the two soft-story buildings he owns in San Francisco. He supports the bill that would require him to retrofit the properties at his expense.

Photo: Lea Suzuki, The Chronicle

Robert Link of S&L Realty walks through one of the two...

Image 3 of 6

Image 4 of 6

A pedestrian walks past the soft-story property of Robert Link (not shown), owner S & L Realty, on Tuesday, February 5, 2013 in San Francisco, Calif. Link owns two soft-story buildings and could have to retrofit the property to increase chances of surviving a major earthquake under legislation introduced Tuesday.

Photo: Lea Suzuki, The Chronicle

A pedestrian walks past the soft-story property of Robert Link (not...

Image 5 of 6

Robert Link, owner S & L Realty, is seen in front of one of two soft-story properties he owns on Tuesday, February 5, 2013 in San Francisco, Calif. Link owns two soft-story buildings and could have to retrofit the property to increase chances of surviving a major earthquake under legislation introduced Tuesday.

Photo: Lea Suzuki, The Chronicle

Robert Link, owner S & L Realty, is seen in front of one of two...

Image 6 of 6

Robert Link, owner S & L Realty, walks through one of two soft-story properties he owns on Tuesday, February 5, 2013 in San Francisco, Calif. Link owns two soft-story buildings and could have to retrofit the property to increase chances of surviving a major earthquake under legislation introduced Tuesday.

Thousands of San Francisco property owners would be required to retrofit their older, collapse-prone buildings at an estimated cost of $60,000 to $130,000 each to improve their chances of surviving a major earthquake under legislation Mayor Ed Lee introduced Tuesday.

After more than a decade of work, the city is trying to ensure that housing for about 58,000 residents and businesses employing 7,000 workers could withstand a major temblor by forcing property owners to make seismic upgrades.

"We've been talking for years and years about doing something, and our voluntary retrofit program doesn't seem to work for everyone because the work is not getting done," said Supervisor Scott Wiener, one of the main co-sponsors of the legislation, which is backed by a majority of the 11-member Board of Supervisors.

"We know that in a major earthquake, soft-story buildings are very likely to be badly damaged if not destroyed," Wiener said.

The city has compiled a list of more than 4,500 buildings that could meet the definition of "soft-story" buildings - those multistory, wood-frame buildings with a garage, large windows or similar opening on the ground floor.

City officials are refining the list to determine which buildings would be covered under the legislation introduced Tuesday and estimate that about 3,000 buildings would probably require retrofits. The work primarily entails reinforcing wood construction with a steel frame. A 2009 city-commissioned report recommended mandatory retrofits for the 2,800 most-susceptible buildings at a total cost of $260 million - but said that could avert $1.5 billion in damage after a major quake.

Lee said in a statement Tuesday that the city would develop ways to help property owners defray costs, although those details are not included in the legislation.

"We are taking the necessary steps to protect our residents and make sure that San Francisco is America's most resilient city," he said.

What qualifies

The proposed regulations would affect only wood-frame soft-story buildings built before 1978, that are at least three stories high and contain five or more dwelling units. The requirements do not apply to single-family homes. Buildings retrofitted within the last 15 years are also exempt.

If approved by the supervisors, the city would begin sending notices 60 days later to property owners indicating they may have a soft-story building, Lee's administration said.

Property owners would then have one year to have an architect or engineer do an inspection to determine whether their building needs to be retrofitted.

If so, buildings would be slotted into four tiers with four to seven years to do the upgrade. The first group would include those soft-story buildings that house day care centers, senior facilities or other vulnerable populations. The next tier would include large residential buildings with at least 15 units.

Owners who fail to upgrade their buildings would be subject to fines and, potentially, liens and lawsuits.

Concern about rents

The topic has been contentious for years.

While supportive of the upgrades, tenant advocates are concerned that rents will increase because 100 percent of the retrofit costs could be passed on to renters. The city's voluntary retrofit program, which waives some fees, has had few participants because the cost savings is nominal, a city controller's analysis found.

Only about 50 property owners used the voluntary program, said Bill Strawn, a spokesman for the Department of Building Inspection. City permit records show those retrofits ranged in price from $8,000 to $5 million, with most between $30,000 and $75,000.

The legislation introduced Tuesday to mandate the retrofits is the result of a proposal Mayor Gavin Newsom began in 2010.

Newsom also wanted to create a special tax district that would allow property owners to use the city's strong bond rating to borrow money for the work at a reduced rate. The idea was shelved by federal regulations that have recently been revised. Separate legislation is planned that would include that element.

Many property owners who had a hand in drafting the proposal support it.

"It's not going to be a pleasant experience for everybody. There are going to be some uncomfortable tenants and owners, but ultimately the work needs to get done," said Janan New, the executive director of the San Francisco Apartment Association, a landlord group.

Robert Link, president of the association's board of directors and owner of S&L Realty, called the proposal "a win-win."

"It will compel owners to safeguard their building while also safeguarding their investment," said Link, who owns two properties that would require retrofitting under the law. Link estimated the cost of retrofitting a $3 million, 12-unit apartment building at about $150,000.

New said it is unclear how many property owners would go through the bureaucratic process to raise rents to pay for the retrofits, but Link estimated that most would.

Ted Gullicksen, director of the San Francisco Tenants Union, said some rents in smaller buildings could go up $100 per month. He doesn't support the legislation without specific eviction and rent-increase protections.

Doing one major renovation is also often an opportunity for other capital improvements, which may give landlords incentive to drive out tenants, Gullicksen said.

"Once the landlord has them out of building (temporarily), they have significant leverage, and start using coercion, buyouts and threatening their right of return," Gullicksen said. Lee's administration says that very few residents will be displaced during the work.